Manufacture of artificial silk or the like



* Patented, May 31, 1927. I

1 ant invention so long UNITED STATES JOE onernan zn ano wrcn, or LONDON, ENGLAND.

MANUFACTURE OF ARTIFICIAL SILK 01% THE LIKE.

No Drawing. Applioation flled Ang ia-12, 1926, Serial No. 125,916, and in Great Britain May 6, 1925.

This invention primarily relates to the drying of artificial silk and the like prepared from acetylated solutions of cellulose acetates but it is of wider application as will be indicated below.

The invention is of particular use in com nection with the production of artificial silk according to the processes of my British Specifications Nos. 139,232, 190,732, 196,641,

200,186, 203,599, 227,134,244,14s and 9,397 of pound or mixture into a mechanically strong thread or film,

To enable this conversion to be eifected,

successfully I have found that the thread must be permitted to contract on formation into a dry thread to a very considerable extent indeed. It is best ex ressed by stating that the thread or film s all be allowed to contract freely.

Winding spools made to permit reduction of tension in drying materials including artificial, silk, artificial horsehair and yarns have already been proposed and these if made of suitable materials, sizes and dimensions may be employed according to the presas they are arranged to permit free shrin age of the aoetylation' mixture or the like on its formation into a dry thread or film.

The invention consists in a method ofv forming dry artificial silk threads, films or the like according to whicha freshly formed.-

silk thread is permitted during the drying operation to contract substantially freely and is dried on a resilient bobbin or spool in such a manner that undue tension is avoided and the tension due to the initial windin operation increases slowly and continuously during the drying operation.

In carrying the invention into effect in one form b way of example a spool is constructe from a sheet of perforated aluminium about 4 to 6 inches wide and about 6 to 7 inches long. Thisis'rolled into the shape of a spiral. A number of similar spools are thus made and placed on spindles, the outer diameter of the spools being preferably as closely as possible the same. On the spools freshly coagulated artificial silk is wound. When the appropriate length of thread has been wound on to the spool the latter is removed from thespindle and dried, for example in an oven at the appropriate temperature. During drying if the thread shrinks the formation of the spool prevents undue stresses in the fibre. 4

According to a modification in place of forming the spool as a spiral it may be formed as a gapped cylinder. Durin winding of the thread on tothe c linder t e ap is preferably closed b a b ock or we go, this being removed place.

In place of either of the above forms any other method of spring-supporting the thread in such a manner that undue stresses are not set up during drying may be employed, for instance springs such as clock sprmgs can be used inside a light split or spiral tube or band.

The spoolsif made in the form of a spiral or cylinder or in any other manner may be formed from metal or other material of uniform or non-uniform thickness.

The'spools may be made of any .kind of metal, for example of bronze or aluminium, or of any other material possessing appropriate resilience, for example celluloid.-

The spools may be made of perforated metal or other material or of imperforate substances.

The dimensionsof the spools both in length and width may be varied as required.

The spools when on spindles and while the thread is being wound may be kept in their form and diameter by two rings or bands or plates fixed on'both ends of the spool inside oroutside or both, these being removed during the drying process. Spools so prepared can be fixed on spindles in an a propriate and convenient manner, pre era y easily detachable form.

The invention may be applied in the manu facture of artificial silk in the form of threads, ribbons or other films, filaments or the like by the processes of the Zdanowich British specifications numbered as above or artificial silk or the like prepared by any other process where a contraction is likely to occur. and tension is to be avoided, for exin an ample the viscose. process, other cellulose acetate processes, whether dry spinning be employed or not, cuprammonium processes and collodion silk processes.

I It is found that by the present invention, excellent results are obtained even with the finest counts of silks, such as 2 to 3 denier per separate strand;

Having now described my invention, what 1. I claim as new and desire to secure by Letters Patent is p a 1. The process which consists in theextrusion of a directly spinn'able acetylated solution of cellulose acetate into a coagulating trusion of a directly spinnable acetylated solution of cellulose acetate into a coagulating bath, Winding of the forming filament on a freely contractible spool under substantially'no tension and drying the so wound filament in place on the spool.

In testimony whereof I have signed my name to this specification.

JOE OLGIERD ZDANOWIGH. 

